[N3DXT]

Just looking for a few recommendations really.

My 2007 BUB engined MK5 R32 (which is definitely intent on bankrupting me) is now displaying an 'oil pressure light - turn off engine immediately' when warm. I had it fully serviced in December at the local VW dealer (my invoice shows it was filled castrol edge 5w30). I've driven less than 150 miles since then due to work being full on. I had just picked the car up following a full suspension rebuild of front and rear suspension with new shocks, springs, top mounts, all new bushes, new rear diff cradle etc, filled it up at the petrol station ahead of the journey home and then had to take it straight back to the garage for them to look at as the oil warning message came on

The garage has run it up to temp and say the oil pressure is too low for the oil pressure sensor when it reaches warm, they have recoemmended not to drive it as they think it could be bottom end bearing issues etc so it's being trailored home tomorrow whilst I work out what to do next.

I need someone who can drop the sump, inspect the bottom end and advise what's needed. I also need a new sump if any one knows where I can pick one up for less than the £300 the dealer wants

The engine was running nicely with no knocking issues or worrying noises at all, it has 73k on the clock and a reasonable service history so has been looked after for a good part of its life.

 

[VelovetAndy]

73k, no nasty noises and a decent service record........I think you would have to be really unlucky for the problem to be main or big end bearings ( the latter would knock under load and the former rumble. ) . My first port of call would be to ask the garage to connect a mechanical oil pressure gauge to verify ( or otherwise ) the oil pressure cold and warm both at tickover and at, say 4000rpm. Until you have that reliable data , it is very easy to jump to expensive conclusions when the real fault may well lie elsewhere .

 

[rgh0]

Put in 5W- 40 and see what happens, you should get higher pressure and this was the original spec viscosity for the engine I believe ( at least it was on my Mk4 R32). I agree also around use of a mechanical gauge to check the actual pressure.

cheers
Rohan

 

[N3DXT]

Cheers Andy / Rohan for the replies.

The garage say they've tested the oil pressure with a mechanical gauge (so that they could eliminate a faulty oil pressure sensor and / or oil pump), that has shown that the pressure drops off when the engine gets up to temperature. The garage are a specialist VW one and have a lot of experience in engine building so I half trust what they say ...........but after being presented with a massive bill for the suspension rebuild I'm reluctant to spend any more money on it for a while even if that means laying it up. With the way the bill spiralled I'm not sure I could ever afford to take it back there and say here's a blank cheque, do what you think is necessary.

I'm going to dry store it now until next spring and then get it trailored to a specialist, I only bought it last September and somehow am already over £10k lighter (and that doesn't include the purchase price). Looks like I'm in to this for a longer haul than anticpated. Whoever buys this off me when I let it go will be getting a stack of receipts and probably won't have to do anytng but basic servicing for years.

Sorry if I'm coming across as grumpy, I'm just a bit p'd off with how little I've been able to use it since buying it due to there being one issue after another.

 

[Lucifer]

What the hell you spend 10K on ?

 

[N3DXT]

What the hell you spend 10K on ?

Replacement wings and front end respray
Manifold back exhaust (would have been more if you weren't around)
Full suspension replacement inc rear subframe and all the stuf that was found when that was carried out
Tyres
Servicing (full inspection service plus haldex, dsg, brake, AC,
Braided brake hoses
Replacing missing / damaged trim pieces

It adds up quickly for sure.

 

[rgh0]

Have you tried a top quality 507 approved 5w-40 oil ?
What are the actual pressures measured. i.e. cold idle, hot 3000 rpm and hot idle ?
Are oil temperatures OK ?
Have you changed the filter to ensure that's fitted correctly

Depending on the results of above and If no noises from bottom end, problem could be oil pump wear or relief valve stuck open so I would probably pull the pump and cooler assembly off first to inspect

 

[N3DXT]

Have you tried a top quality 507 approved 5w-40 oil ?
What are the actual pressures measured. i.e. cold idle, hot 3000 rpm and hot idle ?
Are oil temperatures OK ?
Have you changed the filter to ensure that's fitted correctly

Depending on the results of above and If no noises from bottom end, problem could be oil pump wear or relief valve stuck open so I would probably pull the pump and cooler assembly off first to inspect

The oil used at the last service was Castrol Edge 5w30, I can't fully remember the pressures that I was advised by the garage (I was a bit in shock and feel I have been fleeced on the labour side of the suspension rebuild job so it was difficult keeping calm / polite with them). They did say when the engine temp was cold the pressures were good, when the car was warm and above idle speed once again they were good. the issues only occurred when the car was warm and at idle. I think they said at warm the sensor can read from 0.75 bar or psi and the car was showing 0.66 bar or psi at warm idle which was below the sensor tolerance hence the oil pressure light.

I've got the car back now so I'll decompress for a bit and then work out what do to next. Oil temps weren't mentioned as an issue by the garage and filter appears to be fitted correctly. Because of a previous garage's bodge (prior to me getting the car) the sump plug is has been sealed in, I think some someone cross threaded it and this was the fix. Bascially I can't drop the sump off to check the oil pump until I get a replacement unit, a new genuine sump is around £300.00 and I can't find a genuine used unit for sale at the moment so if nothing turns up in the next month I'll have to order one from the dealer.

 

[rgh0]

It sounds like your just below the sensor alarm limit at warm idle. The engine was designed for 5W-40 oil. Using 5W-30 oil will result in lower warm idle pressure. VW dealers appear to be now using only 5W-30 oils due to this being the specification for the later cars but this may cause an issue with higher mileage older cars design for 5W-40 with low hot idle pressure. You could even try a 5W-50 oil if 5W-40 does not fix the problem as this would help compensate for bearing and pump wear compared to original as new design

Most engines are designed for minimum hot idle pressure of around 1 bar and minimum hot running pressure at 3000 to 4000 rpm of around 2 to 3 bar. Thus oil pressure warning light set at 0.75 bar is normal. Did the garage say what the oil pressure was with the engine hot and 3000 rpm ? If it was in the 2 to 3 bar range then its almost certainly just a problem with the 5W-30 oil in combination with an older engine that has some wear. The low pressure at idle it does not mean the engine or pump needs a rebuild

regards
Rohan

 

[rgh0]

How did the dealer change the oil if the sump plug could not be removed due to the damaged threads or did this occur later
You also should be able to fit a helicoil or similar thread repair devices into the sump to repair the damaged threads rather than replace the sump.

cheers
Rohan

 

[Alan c]

Did you have this problem before it went for it's service. Because they run it to check for oil leaks. And as last comment how did they change your oil.

 

[rgh0]

The car appears to have been serviced in December and then sat around having major suspension and rust repairs for for 6 months and now immediately after it back the low oil pressure light comes on when hot and idling. Its possible I guess that the oil also got changed during this 6 months after the service for some reason as its not clear when the sump plug was stripped and glued back in ?

My bet is still that the problem would be fixed with top quality full synthetic 5W-40 or 5W-50 oil.

 

[N3DXT]

Hi All

Thank you for all your replies (especially Rohan), I've had some time to digest the situation a bit more now.

The car was serviced in December by VW, due to the issue with the sump they siphoned the oil out of the oil level sensor, another issue they found during this service was a broken rear spring but as I was in the process of collecting the parts for a full suspension rebuild I advised them to leave it as it was and then I'd replace all suspension components at the same time, I knew I'd only be driving a few hundred miles at most before I got the suspension changed along with a 4 wheel alignment and so the car has only been used a handful of times since (only mentioning that to show why it wasn't being used).

The garage that carried out the susupension work didn't touch the engine. The milage when VW changed the oil on 22.12.2021 was 73219, I picked up the car from the suspension garage with the mileage showing 74399. I had no oil light warnings between the December 2021 and April 2022 when I dropped the car off at the suspension garage. The journey to drive it down there took about 75 min and weather temps that day was around 18 degrees. From picking the car up to the oil light coming on was less than 2 miles (it was rush hour so I was sat idling for quite a while), weather temps on that day were at least 25 degrees.

The suspension garage said at warm the pressure was around 3 bar. I can't remember the exact figures.

The plan now is to book it in with a different VW specialist and get them to drain the oil, drop the sump and replace the sump with a new one, inspect the bottom end and oil pump and if nothing untoward is seen then just refill with higher quality oil 5w 40 or 5w 50 oil to see whether that makes the difference. On cold idle the engine sounds perfectly healthy to me.

Picture of the sealed in sump plug below (not the clearest of pics, this is what the VW dealer sent me back in December)

 

[VelovetAndy]

If you are going to the expense of dropping the sump ( and I can see why ) , then any competent garage would be able to repair the sump rather than you having to stump up for a new one . A helicoil insert would do the trick and be a reliable fix, as would drill and tap oversize . Anyway, hope it is nothing more that the oil grade . Must admit I use 5-40 in mine .

 

[N3DXT]

Hi Andy

Cheers, I'll speak to the garage about that when I book it in tomorrow, I'm not expecting them to be able to take it in for 2 - 3 weeks.